1. Field of the Invention
The present invention relates to a switching power supply device that uses a non-linear control system and to an electronic apparatus (e.g., television) that uses the switching power supply device.
2. Description of Related Art
FIG. 14A to FIG. 14C are each a circuit block diagram and an operation waveform view that show a conventional example of a switching power supply device which uses a non-linear control method, of which FIG. 14A illustrates a switching power supply device that employs a hysteresis window system, FIG. 14B illustrates a switching power supply device that employs a bottom detection on-period fixing system, and FIG. 14C illustrates a switching power supply device that employs an upper detection off-period fixing system. In the meantime, any of the switching power supply devices illustrated in FIG. 14A to FIG. 14C is a voltage step-down type DC/DC converter that steps down an input voltage Vin to generate a desired output voltage Vout.
In the meantime, as an example of the conventional art related to the above description, there is JP-A-2012-115047.
The switching power supply device using a non-linear control method easily achieves high efficiency during a light load period compared with a switching power supply device using a linear control method (e.g., voltage mode control method and electric current mode control method). However, in recent years, as energy saving attracts more attention, power loss (power consumption during a standby period and the like) of an electronic apparatus during a light load period is becoming unable to be negligible, and also the switching power supply device using a non-linear control method is required to further increase efficiency during a light load period.